Sharks

Ancient predators

Sharks have been around for hundreds of millions of years. While many of us may be familiar with a few shark species, there are over 400 of them found throughout the world’s oceans, from the 20 cm-long dwarf lanternshark to the 12 metre-long whale shark. Most sharks are efficient predators with a highly developed sense of smell, hearing and sight. They can detect their prey’s scent from a great distance. Sensitive eyes see clearly even in the dim light of the ocean depths.

Most sharks are carnivorous and eat fish (including other sharks) as well as larger animals such as seals. Others, like the whale shark and the basking shark, filter feed on tiny plankton or krill. Despite their fearsome reputation as ruthless predators, sharks are much more likely to be killed by humans than the other way around. WWF is working to stop overfishing of sharks to make sure these magnificent animals continue to thrive in the oceans, and to reduce demand for unsustainably fished fin and meat.

Why are sharks important?

The vast diversity of sharks globally play important roles in keeping our oceans healthy, all the way from bottom-feeding dogfish and nutrient-cycling basking sharks to top predators like Greenland and great white sharks. The decline of sharks spells trouble for the ocean. Removing these key species has serious consequences for marine ecosystems, which in turn has repercussions for people everywhere.

What WWF is doing

On-the-water solutions

To address the threat of unintentional capture, or bycatch, WWF is working with partners from industry, government and academia to find practical on-the-water solutions.

Innovating technology to reduce bycatch
We work with commercial longline fishermen off the coast of Nova Scotia to conduct experiments with special materials placed near hooks to repel sharks. The materials include rare earth metals and other substances that produce minute electromagnetic fields, which have deterred target species from latching on in other fisheries.

Not all experiments are successful, unfortunately. Initial results for this longline fishery indicate that the use of the substances were not effective in reducing the bycatch of the main shark species caught, blue sharks. This is likely because - as an oceanic predator - blue sharks rely more on vision than their electro-sensory system. We will also be exploring the use of these substances in other fisheries, like bottom longline, which also have significant bycatch of sharks.

Developing catch, handle, and release practices
In collaboration with Art Gaetan, a recreational shark fisherman with over 20 years of experience, we developed best catch, handle and release practices to ensure sharks caught in recreational fisheries are handled and released in the best condition possible to ensure survival. In 2015, we worked with recreational shark fishing operations in the Maritime Provinces to adapt these practices to develop a Code of Conduct for Recreational Shark Fishing.

Understanding the threat of fishing

Bycatch hotspot analysis for all elasmobranchs
In collaboration with researchers at Dalhousie University, data on the bycatch of sharks and their relatives in commercial fisheries was analyzed with the goal being to identify bycatch hotspots in Atlantic Canadian waters, levels of bycatch for at risk shark species and possible mitigation measures. Several areas emerged which appear to be of significance for various shark species, such as porbeagle, blue and shortfin mako sharks. Porbeagle shark hotspots were consistently found on Browns Bank and Emerald Basin. Browns Bank and Emerald Bank were also important areas for shortfin makos and blue sharks, respectively. Highest cumulative impacts are localized in a few key areas on the Scotian Shelf in the Bay of Fundy and Gulf of Maine.

A guide for identifying sharks
To ensure the accurate identification of sharks, skate, rays and chimaeras (collectively termed Chondrythians) by fisheries observers on Atlantic Canadian fishing vessels, we developed an identification guidebook and provide training in collaboration with observer companies.

In 2015, we will be launching Sea ID – an electronic identification App for large marine species in all of Canada’s oceans, including cetaceans, pinnipeds, sea turtles, Northwest Atlantic corals & sponges, many marine fish and all chondrythians.

Tracking bycatch and post-release mortality
To improve the collection of shark-related data by commercial and recreational fishermen, in March 2011, a multi-stakeholder meeting was convened, in collaboration with industry, to standardize the data collection protocol to assign the body condition of live sharks caught in commercial fisheries or for research (used as a proxy to determine how many sharks released alive survive). These measures will aid in the investigation of incidence of bycatch and post-release mortality of sharks impacted by our commercial and recreational fisheries.

Obtaining knowledge and perspectives from industry leaders
In order to better understand the current situation for shark populations in Atlantic Canadian waters, we worked with commercial fishermen to gather their traditional fishing knowledge. To do this, we conducted a survey of fishermen to get their perspectives regarding sharks, shark capture, bycatch hotspots and mitigation measures that have been tested by the fleet.

National protection and improved fisheries management

Collaborative discussions
WWF-Canada is committed to working with partners to address the main priorities for shark conservation in Canada. Following the first Atlantic Shark Forum, held in Halifax, Nova Scotia, and the Pacific Shark Workshop, held in Vancouver, British Columbia, top national priorities were identified that, if addressed, would significantly advance conservation and management of sharks and inspire collaboration between different interest groups. View the final report on the Atlantic forum and Pacific workshop.

Species at risk, fisheries management and fisheries sustainability certification
We are committed to ensuring the accurate assessment, protection and recovery of Canada’s species at risk. To accomplish this, we engage on a number of processes as defined by the Species at Risk Act, including the assessment of species by the Committee on the Status of Wildlife in Canada (COSEWIC), the development of recovery strategies and action plans as well as in the identification of habitats critical for their survival. We also engage with Fisheries and Oceans Canada to ensure fisheries management plans accurately consider impacts to non-target species and adequately address any concerns regarding the take of these species through the implementation of effective conservation measures. Where necessary, we are active stakeholders in fisheries eco-certification processes to ensure concerns related to at risk marine species are considered and adequately addressed during the assessment and condition implementation phase.

WWF-Canada’s work on the conservation of shark species in Atlantic Canada is supported by the Government of Canada Habitat Stewardship Program for Species at Risk, CSL Group Inc. and the Canadian Wildlife Federation. Dr. Aurelie Godin’s PhD research was supported by an Industrial NSERC scholarship.

Shark Basics

Species: More than 400 globally, more than 20 in CanadaMaximum weight: Up to 10 tonsLength(varies by species): 20 cm to over 12 m

Adopt a blue shark

Threats

In Canada, unselective fishing practices, particularly the unintentional capture of sharks in longline fisheries targeting tunas, swordfish, and groundfish are a major factor driving shark populations to decline.

Bycatch
Bycatch, or the unintentional capture of non-target species in commercial fisheries, is perhaps the single most significant threat to sharks in Canadian waters. Little is known about the distribution of sharks in Canadian waters, and there is still a great deal more to learn about how to minimize the incidence of bycatch and overall shark mortality. Learn more about bycatch.

Demand for shark fins
Shark ‘finning’, the removal of only the fins from sharks and dumping the remainder of the animal while at sea, is illegal in Canada; however, Canada is importing unsustainable shark products, including fins, for consumption and, globally, the growing trade of shark fins has become a threat to many shark species. The fin trade today is considered to be a primary driver in shark exploitation.

Changes in the marine environment
Destructive fishing activities, pollution and coastal developments can have serious impacts on marine habitats upon which sharks depend. Climate change impacts on the marine ecosystem can also be a cause of concern for sharks, particularly in terms of how population distributions and habitats for sharks, as well as their prey, may be affected.

Did you know?

Twenty-eight species of shark have been reported in Canadian waters; fourteen in the Pacific and twenty in the Atlantic and Arctic. Close to half of these species are considered to be globally threatened.

Blue sharks are found off the coast of every continent except Antarctica.

The whale shark is the largest of all fish and can grow up to 12m long and weigh up to 12,000 kg. However, although its jaws can be over 1m in width, it is armed with the tiniest of teeth.

The fastest shark is the shortfin mako shark which can reach speeds of 30-40mph. It can also leap up to 9m above the surface of the water.

The megamouth shark is the rarest and most mysterious pelagic shark species. It was only discovered in 1976, and has only been seen 41 times since.

Porbeagle sharks are unique in that they have been known to play tag with other porbeagles, pass seaweed to each other, and toss driftwood out of the water in a manner similar to dolphins.

Most oceanic sharks must keep swimming forwards to force seawater through their open mouths and over their gills to breathe - otherwise they would suffocate.

The Caribbean reef shark is known to rest motionless on the sea bottom or inside caves.

When threatened gray reef sharks display a distinctive hunched posture, bending their body into an "S" shape. They are known to be territorial and will warn off other shark species.

The oceanic white tip reef shark is nocturnal and is often seen resting on the bottom of the sea during the day, sometimes in small groups.

Cruising coastlines in large schools, blacktip reef sharks often jump out of the water during a feeding frenzy on schools of fish.